But with millions of souls and millions of donations at stake, critics say that many bogus merchants of faith are turning huge profits with false promises.

Enterprising evangelical pastors benefit from a total lack of regulations, Refkalefsky said. Many pastors lure new worshipers with visions of prosperity and health, he added.

To those in his church, Brazilian evangelical Pastor Arodo offers not only to exorcise inner demons or to counsel couples, but to provide chiropractic care and promises of wealth.

When asked whether the Catholic Church can compete with his brand of Christianity, Arodo told "Nightline," "Absolutely not, because... what I have is a gift from God. It's not mine. It's a gift from God."

At Arodo's church, believers line up to offer donations, and in return he splashes them with his own special holy oil.

"Don't skimp on an act of God," Arodo told his worshipers. "Stand up and come here with your money in hand."

"It's a very informal business, because the money just [goes] directly from the wallet of the member to the wallet of the pastor of the church," professor Refkalefsky said. "There's no control of the money."

That has made salvation a booming business. "The number of churches [is] rising more than the number of the members," Refkalefsky said.

Nowhere is the growth more apparent than in Sao Goncalo, Brazil, which, by some estimates, has more churches per square mile than anywhere else in Latin America.

Sao Goncalo's most popular child healer is 10-year-old Alani Santos, who has been drawing believers to her father Adauto Santos' church since she was 3.

Alani has become a local celebrity, appearing on talk shows with her dad and even hosting an Internet radio show with listeners from around the globe.

"I don't feel any pressure from my family," Alani told "Nightline." "If I don't feel like doing it, they let me. And I like doing it, so I'm never going to stop."

Croatian Daniel Nesak, who said he was shot in the head during a war, leaving the left side of his body partially paralyzed, underwent years of painful operations and therapy. Desperate for a miracle, he traveled halfway across the world to Alani's church.

After experiencing her healing touch, Nesak attempted to grip a microphone stand with his paralyzed hand to test the miracle, but he was unable to do so."It didn't change physically much, maybe next time," Nesak told "Nightline" immediately after the exchange.

"People that don't know this, people who've never seen this ... they don't know it, so it's easier to criticize," Santos told "Nightline." "It's easier for the person to believe a lie than the truth, you know?"